Roller grinding mill



Dec. 10, 1940. H. F. WINSLOW 32,224,330

ROLLER GRINDING MILL Filed July 21, 1937 ATTORNEY Patented Dec. 10, 1940UNITED STATES PATENT orFl-cr;

2 Claims.

This invention relates to improvements in roller grinding mills of thegeneral class employed in grinding printing inks and various other kindsof viscous materials.

As ordinarily constructed in mills of this class the grinding rolls arerotatively arranged in multiple pairs, one of each pair beingnon-adjustably mounted at opposite ends in bearings fixed to theopposite side-frames of the mill, and the opposite rollers of each ofsaid pairs being rotatively supported at their opposite ends in movablebearings slidable lengthwise upon said frames and arranged to eifectequal adjustments at the ends of said opposite rolls by means ofhandscrew shafts l'5 rotatably mounted in said movable bearings andprovided at their inner ends with external screw-sections engaginginternally threaded portions of said fixed side-frames, see enlargeddetail section Fig. 3, the outer ends of said hand-screws being alsoprovided with manually operated driving wheels adapted to urge the pairsof rolls together and eflfect a uniform grinding action the full lengththereof. The grinding of the material produces a heating efi'ect whichacts to expand and enlarge the diameters of the rolls, causing anexcessive increase of pressure between the rolls and necessitatingconstant attention and readjustment of the rolls.

A three roller mill is herein shown consisting of a non-adjustablecentral grinding roll mounted at opposite ends in bearings fixed to theopposite side frames of the mill, and on opposite sides of the centralroll cooperating rollers are disposed and adjustably mounted withrespect thereto in movable bearings to form double grinding surfaces,between which the material to be ground is caused to flow.

The objects of the, present invention also include means containinghydraulic chambers manually actuated by hand-screws disposed in theseveral movable bearings and arranged at the opposite ends of each ofthe adjustable rolls and adapted to inwardly force the latter towardsaid laterally fixed or non-adjustable roller.

Also means actuated by the hand-screws for moving the adjustablegrinding rolls in opposite directions.

Also means including an auxiliary hydraulic device leading to thehydraulic chambers of the adjustable grinding roller of a pair of rolls,and provided with adjustably weighted means adapted to automaticallymaintain a predetermined pressure between the grinding rolls.

Also the provision of a pressure gauge. connected to the hydraulicpipe-line for visibly indicating pressure variation.

For further comprehension of the invention, and of the objects andadvantages thereof, reference is had to the following description andaccompanying drawing, and. to the appended claims in which the variousfeatures of the invention are more particularly pointed out.

In the drawing, Figure 1 is a ground plan showing a threeroller grindingmill provided with the roll-adjusting means embodied in the presentinvention. Figure 2 is an elevational View showing the ends of therollers and the hydraulic connections bearings 6 in which arerotatablyimounted the 1 journal ends of the-central grinding roller 1,adapted for adjustable engagement on opposite sides by the rolls 8 and9, the two last mentioned rolls being journaled at their opposite endsin the elongated bearings l0, slidably mounted on the upper flanges -I lof the frames 5, the bearings being retained in movable positionlengthwise of frames as indicated by the side gibs 12, shown in Fig. 4,which slidingly engage the lower surfaces of the frame flanges ll.

As shown in Figs. 1,2 and 3, the outer ends of the several movablebearings H] are each provided with a cylindrical hydraulic pressurecylinder l3, fixedly securedv thereto in any approved manner, seeenlarged'detail section Fig.3, the .same being internally fitted with apiston I4 having the usual hydraulic packing ring and provided with acentral operating hand-screw shaft IS the inner end thereof beingthreaded and engaging a correspondingly screw-threaded lug I6 formed inthe opposite outer ends of the fixed side frames of the mill.Intermediate its ends the hand-screw is formed with a fixed collar I1and is rotatively supported exteriorly of its threaded portion by thevertical end flange l8 of the bearing l0 and by the bearings formed bythe hub of the hydraulic cylinder l3 and the piston M, the outer end ofthe hand-screw being fitted with a hand-wheel 20 secured thereon by apin I9 extending through the hub of the wheel and the screw-shaft. Bymeans of the handwheel the screw may be rotated within the fixedthreaded lug l6 and inwardly forced together with the hydraulic pistonl4, the latter acting in opposition to the fluid contained within thehydraulic pressure space 2| to inwardly urge the movable bearing l0together with its adjustable grinding roller into the desired operativepositions. By rotating the hand-wheel 20 in its 0pposite or releasingdirection, the respective spacing between the collar l1 and flange IIIwill serve to space the pairs of grinding rolls for cleaning ordismantling, purposes.

Cooperating with the hydraulic pressure cylinders l3 shown in detail inFig. 3, are a pair of pressure regulators or bellows 50 similar to eachother and adapted for connection to the two pairs of grinding rollers Iand 8 and l and 9,

both mounted on a single side-frame of the mill. Each regulator orbellows includes an upright 25 mounted upon the upper flange ll of theframe, and formed with said upright between its ends is an internallycylindrical casing 26 provided with a closed bottom and open top.Adjacent the upper end of the upright 25 a guideblock 27 is detachablysecured and arranged to slidingly support for vertical movement apresser bar 28 having at its lower end a head 29 and at its upper end aknife-blade holder 30 provided with set-screws 3|, to secure theknife-blade 32, for engaging the V-slot 33 disposed in the lower edge ofthe scale-beam 34 for the support of the latter together with thecounterbalance weight 35, slidable along said beam, and adjustably fixedthereon in conventional manner to permit the vibrating action thereof.

At the upper end of the upright 25, a vertically slotted hub 35 isprovided to receive the upright arm 37, the lower end of which isdisposed within the slot of said hub and in pivotal relation thereto;and at its upper end the arm is folded partially over upon itself toform a bearing surface alined with respect to its opposite pivot point.Secured to the latter bearing surface by a pair of screws 38 is aknife-blade 39 that engages a V-slot 40 formed in the-upper edge of saidscale-beam 34 adjacent an end thereof. The knife-blades32 and 39 arehorizontally spaced lengthwise of the scale-beam a relatively shortdistance apart and they jointly serve as fulcrum points about which thebeam is free to rock Without frictional resistance. For laterallyguiding the beam adjacent the knifeblade 39, a bifurcated plate 4| isprovided, the opposite prongs of which engage the opposite sides of thebeam and extend the-depth thereof plus its movement, and for its supportthe plate is held by the screws, 38 that sustain the knifeblade 39. i

Also for guiding the scale-beam adjacent the knife-blade; 32, see Figs-2and: 4, an, upright guide-bar 42, having at its lower endopposite sideextensions 43, is secured to the guide-block 27, and provided with aslot 44 of definite length to serve both as a lateral guideway for thescalebeam and for limiting the verticalv movement of the same. providedfor the scale-beam consisting of a movable plate 45 provided with jaws46 for enclosing and locking the beam 34 in the position shown, and fordetachablysecuring the same, a pair of alined slots 41 are formed insaid plate and secured in sliding position against the upright guide-bar42 .by the headed screws.48..ex-. tending loosely through said slots intapped re Detachable locking means isalso.

lation into the extensions 43 of said guide-bar 42. The locking plate isalso provided with a finger hole 49 by means of which the lock mayreadily be opened and closed, and the scalebeam operated for detachableconnection, held against vibration, and adapted by means of thebalanceweight 35 to exert a variable downward pressure through thepresser bar 28 and head 29 upon the upper end of the corrugatedhydraulic expansion member or bellows 50 disposed within the chamber 26,the member consisting of a hollow closed vessel formed of expansiblebellows shaped metal, provided at its lower end with a hub 5| extendingthrough the bottom of said chamber 26, and having an hydraulic pipe-lineconnection 52 leading through similar pipe connections 53, 54 and 55from the hydraulic pressure spaces 2! of a pair of cylinders l3 thelatter being associated with the adjustable grinding roller 8. Forindicating the desired variable pressure between said pair of grindingrollers 1 and 8 a gage 56, graduated in pounds per square inch, isconnected by the pipe 51 into the hydraulic line.

In charging the hydraulic pipe-line with liquid fluid, the weightedscale-beam 34 is first locked sures required, provision being made inthe pipeline connections for the escape of air during the forcedadmission of the fluid. In the charging action a sufficient quantity offluid is forced into the hydraulic passages 2| of .the cylinders I3 atopposite ends of the adjustable grinding roller 8 to permit the pistonsl4, acting by the manually operated-screws I5 to effectively fill thesuperficial areas of said pistons, and inwardly force the adjustableroller, 8 into parallel engagement with its opposite grinding roller I.

In mills having multiple'pairs of grinding rollers in which the materialground passes successively between said pairs, difiiculty is ordinarily;experienced in maintaining a constant desirable pressure between therolls of each of said pairs, owing in part to a variable difference withrespect to the clearances between the roller journals and theirbearings, which, under the extreme pressures required, results in theadjustment of one pair of rollers being disturbed by the adjustment ofan opposite pair, as instanced in therollersshown in Fig. 2, in whichthe screw adjustment'of side roller8 tends to shift roller 1 in. itsbearings in' one direction and in the opposite direction when anadjustment is made in the opposite side-roller 9.

In the present invention this difficulty as well as, that of theconstant heating effect of the rollers due to the frictional, slidingand grinding actions between their respective working surfaces have beenmet by providing for each pair -of grinding rollers a regulatedhydraulic pipe-line '52, the fluid pressure of which extends upwardlyand also fills the expansion regulator or bellows 50, the length of thelatter respectively increasing and decreasing with the pressure therein;The counterweighted scalebeam having been set at a predeterminedgagep'oint,'representing as a factor the number of pounds per squareinch of fluid surface effected by the .pistons l4 within their cylindersl3, to show'the total number of'pounds pressure exerted between. a pairof rollers, it will be obvious that a variably regulated hydraulicsetting may be applied to each'of the several pairs of grinding rollerswithin a mill, and be adaptable for operation upon a wide variety ofproducts requiring variable degrees of pressure in its grinding actions.

In the automatic action of the device to control the pressure between apair of grinding rollers, in which an increase of pressure over asetting occurs, as will be indicated by the action of the hydraulicfluid that completely fills the several pipe-lines and regulator orbellows 50 for upwardly expanding the latter, which in turn raises thebalanced scale-beam 33 by means of the intermediate connections 28, 29,3E] and 32, the beam being free for vertical movements about theirpivotal knife-blades. It thus appears that the movements have caused aquantity of the fluid to be transferred from the pipe-line to theexpansible regulator or bellows, in which condition the scale-beam willbe retained in its raised position and the gage held to the desiredsetting. In like manner should the pressure between the grinding rollersfall below the setting, the regulator or bellows and scale-beam would bedepressed under the influence of the weighted beam and cause a portionof the regulator or bellows fluid to be returned to the pipe-line, whilethe gage would maintain its originally desired setting position, itbeing understood that by reason of the non-compressible nature of thefiuid, the quantity thereof used in the transfer would be relativelysmall. Also, as shown, the regulator or bellows and associated balancedscale-beam acts as an automatic measuring valve ready instantly totransfer the necessary fluid in either direction to maintain saidbalance and insure a regulated pressure at all times between a pair ofgrinding rollers throughout their operation.

In cases of accidental entrance of foreign matter into the grinding run,as nails from supply packages, or other more bulky matter, the scalebeamwill be caused to yield and pass the nails between the grinding rollerswith no objectionable operative result, and if the obstacle within therun is beyond the yielding capacity of the beam, the general safety ofthe mill is insured by the provision of safety-pins l9 disposed withinthe hubs of the handwheels 20 which operate the hand-screws I5, the pinsbeing designed to be sheared for the release of the handwheels fromtheir screw-shafts by the obstacle acting to separate the rollersblocked thereby that lead through the movable bearings to said pins.

It is to be understood that the present automatic pressure device may,with comparatively small expense, be applied to existing mills ofsimilar general character in which the pressure adjustments consist ofhand-screws either with or without hydraulic connections. In either ofthese latter types of mills the pressure adjustments between thegrinding rollers cannot be held for any definite length of time owing tothe constantly changing temperature condition, common in all mills. Inordinary mills of the above types the operator is called upon to bepractically in constant attention to the pressure adjustments of thegrinding rollers if the regularity of quantity and quality of output iscalled for; if the pressure between the rollers is allowed to becomereduced and irregular, the quality of the material ground will becoarser and the quantity delivered greater, while if the pressure ismaintained by close adjustment the quality of the material will beimproved by being more finely ground and the quantity of output reducedaccordingly.

On the other hand, if automatic pressure valves are applied to theordinary roller mills having one or more pairs of grinding rollers setto a suitable grinding pressure, the operator may give his attention toa plurality of mills, or other matters and be assured that the millsthus automatically operated will hold such pressure, or other desiredones throughout a required period, and produce a maximum output inconformity with the quality thereof.

It is clear that the grinding action of the rollers causes them toheatand expand and more closely space the roller surfaces and give a finergrinding movement. The only time the rollers are cold is when the millstops work.

On setting the mill to the desired pressure, the scale-beam istemporarily locked in horizontal position and the hand-screws operatedin accordance with the pressure gage.

The beam is then unlocked and as the rollers begin to grind and growwarm the pressure therebetween will gradually increase and lift thescale-beam against the action of its weight by the upward expansion ofthe regulator which in its movement absorbs a small amount of thehydraulic fluid from the pipeline sufliciently to reduce the pressuretherein, and thus maintain the desired pressure, as shown by the gage.

I claim:

i. In a mill, a pair of grinding rollers, one thereof being journaled inbearings fixed to the frame of the mill, the opposite roller beingjournaled in bearings slidable on said frame for adjustment toward andfrom the roller carried by the fixed bearings, hydraulic cylinders fixedto the outer ends of said slidable bearings, pistons slidable withinsaid cylinders to form hydraulic chambers, a hand-screw shaft rotativelymounted within the cylinder and piston of one of said slidable bearings,the threaded portion of said screwshaft engaging a correspondingthreaded section in a fixed portion of said frame, a hand-wheel having ahub mounted rigidly on said screw-shaft exteriorly of the piston, saidhub having an abutting relationship with said piston, whereby rotationof said hand wheel will urge said piston inwardly to decrease the volumeof said hydraulic chamber, or permit said piston to move outwardly toenlarge said hydraulic chamber.

2. In a roller grinding mill, a frame, a pair of grinding rollersrotatable thereon and subject to expansion and contraction fromheatyhydraulic pressure generating means including closed pipelinescarried by said frame, manually operable screw means carried by saidframe to exert through said hydraulic means a desired grinding pressurewith respect to said pair of grinding rollers, a pressure regulator orbellows connected to said pipe-lines and adapted for longitudinalexpansion and contraction movements, an adjustably weighted scale-beammounted on said frame to receive the longitudinal movements of saidregulator or bellows, and. means for horizontally locking said beamincluding a slidable lock-plate provided with a pair of jaws disposed toengage the upper and lower edges of said beam.

HARRY F. WIN SLOW.

